Welding method



Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE HARRY J. MORGAN, OFWALNUT PARK, CALIFORNIA, ASSIGNOR TO I. L. 6'0 M. COMPANY, LOS ANGELES,CALIFORNIA, A CORPORATION 01 CALIFORNIA WELDING METHOD No Drawing.

This invention relates generally to a method of forming hard metalfacings upon softer metal bodies and to compositions for use in suchmethods. It is particularly useful whereever a hardwear resistingsurface is required, such as for the cutting edges of earth boringdrills or other cutting tools, or for other surfaces subjected to severewear or abrasion.

It is an object of this invention to devisea relatively cheap andconvenient method of forming hard metal facings from ordinarilyrelatively expensive carbide forming elements, such as tun sten.

It is a further 0 ject of this invention to devise a method of formingrelatively hard metallic carbide facings which will obviate thenecessity of employing a carbide forming element, such as tungsten, inrelatively pure or uncombined state.

It is a further object of this invention to devise a composition ofmatter which will facilitate carrying out the method of this invention.

Further objects of the invention will ap pear from the followingdescription in which I have set forth the preferred embodiment of myinvention. It is to be understood that the-appended claims are to beaccorded a range of equivalents consistent with the state of the priorart.

It has previously been proposed to utilize elements capable of formingrelatively hard carbides for forming hard metal facings upon softermachinable or other metal bodies. A process of this character isdisclosed in Davies Patent No. 1,613,942, in which process the elementscarbon and tungsten are fused byan electric are upon the surface to befaced. In the Davies process an excess of carbon is supplied so as toprovide a deoxidizing or reducing atmosphere, thus preventing oxidationof the tungsten. The resulting tungsten carbide facing is of extremehardness, being capable of scratching quartz.

In order to render such processes more commercially practical I haveutilized an ordinary commercial powdered tungsten in unwrought conditiontogether with carbon, these materials being generally premixedApplication filed January 1 6,"1929. Serial No. 333,029.

ingredient which materially adds to the costof forming such facings. Inthe present invention I utilize tungsten or like material in a cheapreadily available form, without detracting from the desiredcharacteristics of the resulting facing.

I have discovered that when forming hard metal carbide facings ofelements such as tungsten, by processes such as outlined above,

it is possible to utilize natural oxygen containing ores and oxides of.the tungsten or other element which is employed. Natural ores or oxidesof elements such as tungsten can be secured relatively cheap compared tothe refined elements, and I have discovered that the impurities whichmay be present in such ores do not detrimentally affect the resultingfacing. The ore is plied directly to the surface to be faced and isreduced Slmultaneously with fusing of the same. As a reducing means Ican utilize elements such as carbon or silicon, or by providing areducing atmosphere of gases such as hydrogen. Irrespective of the meansemployed for effecting reduction of the ore, sufiicient carbon issimultaneously supplied so that the resulting facing is a hard carbideof the element or elements sup lied thru the ore.

The preferred element which I supplythru the medium-of an ore or oxidesof the element, is tungsten. The most common ores of tungsten arewolframite (FeMnWO and Hub- I nerite (MnVvO Other natural ores which arenot as common are ferritungsite (Fe O IVO GH O) and ores containingmixtures of tantalite and wolframite. All of these ores contain oxygenin combination with the tungsten, and must be reduced to render thetungsten free to form tungsten carbide.

As a concrete example illustrating the manner in which one of the aboveores can be employed in my method, I can secure good resultsbvthoroughly mixing about 9 pounds of powdered wolframite with about twopounds .of powdered carbon. This material is also mixed with a suitablebinder such as dextrine, and a certain amount of water orothervaporizable liquid is added. This composition is then baked to drynessand is broto be faced, and an electrical welding arc is struck betweenthe face of the body and a dill RFS

carbon or other suitable welding electrode. As the arc is graduallyprogressed over the face of the body in contact with the granularmaterial, this material is fused to form a relatively hard tungstencarbide facing. Generally the facing is applied to iron or steel bodies,and a certain amount of this iron is absorbed by the fused tungstencarbide facing.

The facing resulting from the above method contains from 3 to 10% ofcarbon and is in excess of tungsten. In this particular method a certainamount of the carbon is utilized in reducing the tungsten ore, and inpreventing oxidation of the tungsten, while a certain amount is alloyedwith or is dis solved by the tungsten to form a carbide. If athicker'facing or a facing having a harder surface is required, anotherlayer of the composition is applied and fused upon top of the firstlayer, and similarly a third or any number of layers can be applied. Thesucceeding layers are of progressively increasing hardness, due to thepresence of a progressively lesser percentage of the iron from the body.

In place of utilizing an excess of carbon for effecting reduction of thetungsten ore, I can utilize any equivalent reducing agent, such as anactive atmosphere of hydrogen. For example a reducing atmosphere ofhydrogen' can be utilized by an electrical welding outfit utilizing theatomic hydrogen flame for fusing the composition. When effecting areduction in this manner,the percentage of carbon employed in thewelding composition is correspondingly decreased, since only arelatively small amount of-the carbon is then consumed during thewelding and reducing steps.

While a tungsten ore is the preferred ingredient for my weldingcomposition and method, my process canalso be utilized in connectionwith ores such as tantalum and molybdenum, or commercially availableoxides of these elements, which'can be readily reduced with carbon or bythe use of a reducing gas such as hydrogen, and which will form carbidesharder than machinable steel. Tantalum. and molybdenum are elementswhich will combine with carbon to form relatively hard carbides, andwhose ores can be used in my method. @ther elements capable of forminghard carbides and whose ores or oxides can be utilized in my method, arevanadium, columbium, (which generally oc-' ours with tantalum),titanium, and uranium.

neaaiee mixed homogeneously with carbon together.

with a binder; can be packed in suitable cartons and sold for use incarryingout the method of this invention.

I claim:

1. A process of applying a hard metal fac ingto a softer metal bodycomprising placing an oxygen containing compound of an element capableof forming a hard metallic carbide, together with carbon upon the softermetal body, and fusing the element and forming reducing conditionswhereby the hard metallic carbide is formed on the softer body.

2. A process of applying a hard metal facing to a softer metal bodycomprising placing an oxygen containing compound of tungsten togetherwith a reducing agent upon the surface of the body to be faced, andfusing the compound together with the reducing agent upon the body.

3. In a process of applying a hard metal facing to a softer metal body,the step comprising directly reducing and fusing an oxygen containingcompound of tungsten, upon the surface being faced, in the presence ofcarbon, so that the tungsten forms a hard carbide on the surface.

4. In a process of applying a hard metal facing to a softer metal body,the step comprising directly fusing tungsten ore upon the surface beingfaced while simultaneously supplying carbon, and maintaining the fusionunder reducing conditions.

5. In a process of applying a hard metal facing to a softer metal bodycomprising supplying a mixture of a tungsten ore and carbon to thesurface to be faced, and causing said mixture to be fused under reducingconditions.

6. A process of applying a hard'metal facing to a softer metal bodycomprising supplying a tungsten ore and carbon to the surface to befaced, and fusing said materials upon the surface to be faced, thepercentage of carbon being sufficient to efiect reduction of the ore andto form a hard carbide with the tungsten.

In testimony whereof, I have hereunto set my hand.

HARRY J. MGRGAN.

